Boiler return system



1935- D. B. KNIGHT 2,011,223

BOILER RETURN SYSTEM Filed Nov. 29, 1933 ATTORNEYS Patented Aug. 13,1935 2,011,223

UNITED STATES P AT ENT OFFICE BOILER-RETURN SYSTEM Donald B Knight, Brooklyn, N.Y., assignor to Refrigeration Research Corporation, Brooklyn, N. 12, a corporation of New York Application November 29, 1933, Serial No. 700,162

s Claims (01. 227457) I This invention relates to boiler return sysso that the water flows freely into the container, tems and in particular to 'thosesystemswherein first filling the trap G and entering the boiler, the condensed water is under the same pressure then rising and filling the container D. By regas the pressure in the boiler. I ulating the rate of flow of the water from the Heretofore when the steam has-been condensed mains entering the container D through the at a point below the water level in the boiler, it valve E- the level in container D may be made has been necessary to pump the water back into to rise while the water is at the same time run the boiler by mechanical-means or to use an inning from container D to the boiler through the jector. In the first instance mechanical attenline 9 and the trap G. Therefore, when any de- 10 tion is required and, in the case of thesteam sired level is obtained in the boiler, the level may injector, there is a limit in the temperature of the be permitted to rise in container D, finally filling water handled. Inneither case i'sit feasible to the line H between the radiator and the conoperate continuously or without regard to the tainer. If the pipe forming the line H is not of amount of condensed" water collected. sufiicient diameter to permit air and water to e "It is the object of thisinventionto provide'a pass'freely in opposite directions, the valve "J 15 continuously operating return system for heatat the top of the radiator should be opened to ing plants, wherein theconden sed water is under permit the dis'placed'air to escape while the line boiler prejsslure at a point below the water level H is being filled. The valves E' and F are then in" the boiler, thisreturn system operating withclosed and the burner Bis lighted, the valve E ii out valves or other moving parts. i being closed to prevent more water from enter- Further objects and advantagesof'the invening the'system and the valve F- being closed to tion will be apparent as it is described'in further prevent air from being sucked into the system. detail in connection with the drawing, the sin- At this time the trap G is completely filled with gle, figure of which is a diagrammatic illustration water. l l 28 of a boiler return-system constructed in accord- As the water boils in boiler A, steam passes ance'with the present invention. to the radiator C through the line I and displaces In the drawing, the boiler is shown at A and air inthe radiator which escapes when the valve is heated by a burner B or other suitable means. J isopened. When all of the air has been dis- C is a radiator which is situated below the level placed, valve J is closed and the steam pressure of the water in the boiler and D is a container builds up in the boiler. Valve F is again opened 30 to which the water and steam maybe delivered, and water from the radiator is pushed out this container being above the level of the water through H, D, and F, under the influence of the in the boiler.- Water may be admitted to the steam pressure in the boiler.

container D through a valve E and discharged At the same time the level of water in the l therefrom through a valve F. Thecontainer D inner leg g of the trap G is depressed, the colis connected to the boiler A by a pipe connection umn of water in the line H being counterbalanced g which includes a trap G, which acts as a by the column of water in the line g andits concheck as hereinafter explained, the trap comnections. Inasmuch as steam passes through the prising an" enlarged leg G i which is connected lowest point of the line H it is apparent that the at itsupper end by, a leg 91 with the lower end depression of the water levelin the leg g 'on the 40 of the lined, and is connected at. its lower end boiler side of the trap G would reach to the botwith the boiler A by aleg g .Thlelleg G is protom of trap G if the lowest point of both line I-I vided at its upper end, with a vent cock'lfi. A and trap G were situated at the same level. pipe line I is provided to deliver steam from the Consequently the trap G might be located below boiler to the radiator C, while a pipe linell the lowest point of the line H, but it is pref- 45 serves tolcarrysteam and water from, the radiaerably formed, as shown in the drawing, as a tor C to the container The trap G is formed double trap with an enlargedleg G" through e as a double trap having, theenlarged leg G which steam from the boiler may bubble with- .through whichwsteam from the boiler may bub- -out displacing all of the water therein. Steam *ble without displacing waterwhich is contained from the boiler enters the bottom of the en- .50

therein. l 'larged leg G and passes to the top of the en- The system operates as follows: a larged leg. Since the bubbles have volume the.

' ater from the mains is first admitted to the bubbles of steam displace some of the water in "container D through the valve The valveF the enlarged. leg in their passage upward. The

at the top of the container is opened to the sewer water so displaced isforced through the leg g .155

of trap G. When the steam reaches the top of the enlarged leg it forms a body of steam in the upper end of the enlarged leg. Thence forward any steam bubbling in at the bottom of the enlarged leg forces a substantially equal volume of the steam pocketed at the top of the enlarged leg into the adjoining leg 9' depressing the column of water therein. The level of the water in this leg g of the trap, under the influence of the steam pressure; could descend until the bottom of the trap is reached if further steam could be admitted at the bottom of the enlarged leg. However, this condition cannot occur since the column of water in line H would then be counterbalanced not only by the water in container D and in the line 9' joining the bottom of container D and the trap G, but also by an additional col-- umnof water in the enlarged legG of the trap G. Consequently steam will blow through the line H before the column of water in the leg 9 of Ztrap G can reach the bottom. The double trap is provided with a petcock at the top of the enlarged leg to allow pocketed air to escape While the trap is being filled.

When steam from the bottom or" the radiator enters the line H, clearing it of water, and bubbling into the container D, the valve F at the top of the container may be closed, whereupon the water, in the container flows by gravity intothe boiler through the line g and trap G and is replaced by steam entering the container through the line H.

Inasmuch as steam is continually being condensed in the radiator C, short separated colurns of this condensed water must also pass through the line H, as well as steam, and consequently-the level in the line or does not fall to the point where the inner leg g enters the boiler, but is elevated to a degree dependent upon the number and length of the separated columns of water passing upward in the line H, say to the level KK.

The steam entering the container is condensed to water due to heat radiation. Thiscontinuous condensation automatically adjusts the pressure in the container D to a value sufiiciently lower than the steam pressure in the boiler and radiator to draw up the short separated columns of condensed liquid in the line H, and the condensate, together with the water so drawn up from the radiator, fiows back to the boiler through the line g and trap G.

The operation of the system proceeds indefinitely as long as heat is applied to the boiler, and after the operation is once instituted the trap G has no function whatever since the level in the line Q then stands continually at the level K-K. The only function of trap G is to act as a device ,in starting up the operation to insure that at the outset steam shall blow through line H and not through trap G and line g. An equivalent ipurpose mightbe served by a check valve opening toward the boiler and closing toward container D, or by an extension of the connection g between the boiler-A and the container D to a point below the lowest point'of line H as already suggested.

It will be noted that should the steam blow through line 9 instead of the line H at the outset it would continue to do so indefinitely and no water condensed in the radiator C could be returned to the boiler. J

The requirement for the successful operation of the system is that the rate at which water is delivered through H from the radiator to the container keeps pace with the rate at which steam is condensed within the radiator C.

If this condition is not obtained the short columns of water in H will become progressively longer and the level KK will therefore rise progressively until the container D is filled with ,water. Steamcan therefore no longer pass into the container and the flow through H ceases entirely.

To avoid this, the line H must be made of a generous rather than a small internal diameter and the radiating surface of the container D must be great enough to insure sufficient condensation of steam in container D so that the flow of steam through the line H is adequate and rapid.

The present invention has been embodied in a system wherein the pipes 9, g 9 G and H are each of three-eighths inch iron pipe size and the pipe I of three quarter inch iron pipe size, the dimensions of tank D are seven inches by twelve andone-half inches and the elevation between the lowest point of thepipe H and the bottom of tank D is fifty nine inches. The height of the connection of pipe g to the boiler A is thirty six and one-half inches above the lowest point of the system and the height of the intermediate leg of the pipe G is fifteen inches.

The radiator C, in the system in which the invention has been embodied, consists of two radiators each thirty two inches high, one of twelve sections and the other of fifteen sections. Obviously, the invention may be embodied in systems with dimensions other than those specified above and the foregoing are given as the specific'dimensions of a construction which has been operated in accordance'with the present invention- While the invention has been described with specific reference to the accompanying drawing, it isnot to be limited, save as defined in the appended claims.

I claim as my invention:

. 1. A boiler return system comprising a boiler, a radiator below the water level of the boiler and connected to the boiler, a container of the closed type above the level of the water in the boiler and connected to the lower portion of the radiator, and a connection between the container and the boiler including a device to prevent the blowing through of steam from the boiler in the initial operation of the system.

2. A boiler return system comprising a boiler, a radiator below the water level of the boiler and connected to the boiler, a container of the closed type above the level of the water in the boiler and connected to the lower portion of the radiator,

, nection.

3. A boiler return system comprising a boiler, a radiator below the Water level of the boiler, piping connecting the top of the boiler and the radiator, a container of the closed type above the level of the water in the boiler, piping connecting the bottom of theradiator with the top of the container, and a connection between the bottom of the container and the top of the boiler including a device to prevent the blowing through of steam from the boiler in the initial operation of the system.

'piping connecting the top of the boiler and the radiator, a container of the closed type above the level of the water in the boiler, piping connect ing the bottom of the radiator with the top of the container, and a connection between the bottom of the container and the top of the boiler including a double trap to prevent the blowing through of steam from the boiler in the initial operation of the system.

5. A boiler return system comprising a boiler, a radiator below the water level of the boiler, piping connecting the top of the boiler and the radiator, a container of the closed type above the level of the water in the boiler, piping connecting the bottom of the radiator with the top of the container, and a connection between the bottom of the container and the top of the boiler including a double trap to prevent the blowing through of steam from the boiler in the initial operation of the system, the double trap having an enlarged leg.

6. A boiler return system, comprising a boiler, a radiator below the water level of the boiler, piping connecting thetop of the boiler and the radiator, a container of the closed type above the level of the water in the boiler, piping connecting the bottom of the radiator with the top of the container, means to introduce water into the container, means to vent the container, and a connection between the bottom of the container and the top of the boiler including a trapto prevent the blowing through of steam from the boiler in the initial operation of the system.

7. A boiler return system comprising a boiler, a radiator below the water level of the boiler and connected to the boiler, a container of the closed type above the level of the water in the boiler and connected to the lower portion of the radiator, and a connection between the container and the boiler including a trap to prevent the blowing through of steam from the boiler in the initial operation of the system, the size of the conneccondensing the steam in the radiator, reducing by condensation the pressure in a closed container above the level of the water in the boiler and thereby causing condensed steam in the ra diator to be drawn into the container, and delivering the water in the container to the boiler.

DQNALD B. KNIGHT. 

